1999-2018年黄河源区水土流失动态变化

[目的] 研究1999—2018年黄河源区土壤侵蚀强度等级变化及空间分布情况,为该区生态环境建设和水土流失治理提供数据支撑。[方法] 利用1999,2011,2018年水土流失动态监测成果,开展黄河源区水土流失动态变化分析。[结果] 黄河源区水土流失面积表现为先增加后减少,与1999年相比,2011年水土流失面积增加1.89×10⁴ km²,增幅126%,2018年水土流失面积增加1.01×10⁴ km²,增幅67.33%。从空间数据来看,与1999年相比,77.97%的区域土壤侵蚀强度等级未发生变化,19.33%的区域土壤侵蚀强度等级降低,2.7%的区域土壤侵蚀强度等级增加。[结论] 水土流失面积增加主要与区域暖干化和人类活动引起的草场退化有关。应实施一批重大生态保护修复和建设工作,提升草场质量,改善区域生态环境。     

磨盘山水利枢纽工程水土保持监测通报

大型水利枢纽工程。由于工程施工期长,破坏土地面积大,挖损、堆渣工程量大,势必造成水土流失,给周边环境及下游城镇居民的生产生活带来巨大影响。开展水土流失监测工作,及时发现并有效控制项目建设区及其直接影响区水土流失恶化现象的发生,为工程建设、水土保持生态环境建设提供依据。项目监测在常规监测的基础上,引入以“3S”为平台的高新科技手段,通过定位测量与定量观测相结合、提高监测时效、监测精度。监测内容主要是:生产作业扰动地表监测,各时段水土流失量监测;水土保持工程效果监测。其结论是:磨盘山水库扰动地整治率达标;土壤流失控制比达标;水土流失治理程度达标;拦渣率未达标;植被恢复系数未达标。     

煤矸石发电厂建设工程水土保持效果评价

阳泉市南庄煤炭集团公司煤矸石发电厂位于平定县西郊,项目建设与运行期间共扰动土地面积52.02hm2,造成水土流失面积33.3hm2。据监测资料,经实施水土保持方案,扰动土地整治率达96.4%,水土流失治理度94.4%,土壤流失控制比0.83,拦渣率98.8%,林草植被恢复系数98.8%,林草覆盖率为26.7%,各项指标均达到了建设生产类项目一级防治标准,治理效果显著。     

平凉市水土保持工作的成效与做法

平凉市总土地面积11140.8km2,其中水土流失面积9880.4km2,截至2004年底,全市累计初步治理水土流失面积7789.0km2,水土流失治理程度达到78.8%。多年的水土治理与开发,改善了农业生产条件,培育了农业主导产业,创立了多种生态经济模式,增加了农民群众的收入。其主要做法是:坚持以梯田建设为切入点,狠抓项目建设,大力推进小流域综合治理,培育各具特色的治理开发典型,依法搞好监督执法。     

十大孔兑流域水土流失分布特征及防治对策

[目的] 通过分析十大孔兑水土流失面积、强度及水土流失动态变化,为流域综合治理提供参考依据。[方法] 基于全国土壤侵蚀遥感调查结果和全国水土流失动态监测成果,对比分析流域水土流失及其分布、动态变化。[结果] 十大孔兑流域植被面积占流域面积的63.97%,以中低覆盖和低覆盖为主,分别占植被覆盖面积的48.85%和36.54%。2021年水土流失面积为4374.98 km²,占流域面积的40.63%;与2020年、1999年和1985年相比,2021年水土流失分别减少46.32,3 664.50,4 958.03 km²,水土流失主要分布在草地、林地、耕地和其他土地4个地类上,占水土流失总面积的96.69%。[结论] 十大孔兑依然是黄河流域水土流失治理的难点地区,高强度侵蚀减少与年度监测成果未考虑沟道侵蚀有关;该区应坚持以“以沙棘种植为主的植被建设,以淤地坝建设为重点的工程布局,以锁边固沙为前提的治沙方针,大力推进拦沙换水试点工程”的流域综合治理策略。     

南汀河流域干流河谷区水土保持发展战略研究

南汀河是一条流往缅甸的重要国际河流,干流河谷区土地总面积2 411.84 km2,水土流失面积815.97 km2,平均年土壤侵蚀量约267.31万t,水土流失导致可耕地资源大幅减少,生态环境恶化,严重影响着当地经济社会的可持续发展,同时对下游缅甸国造成了影响。到2009年,南汀河干流河谷区将完成水土流失治理面积734.37km2,占南汀河干流河谷区现有水土流失面积的90%以上,水土流失得到基本控制,森林覆盖率由治理前的13.55%提高到38.70%,实现生态环境的良性循环。提高土地利用率和劳动生产力,促进土地利用结构和农村产业结构的合理调整,带动区域经济发展,促进农村两个文明建设和社会进步。     

江苏省火电类生产建设项目水土流失特点与强度分析

根据江苏省火电类生产建设项目水土流失典型调查资料,运用SPSS与Excel软件,对单位面积土石方挖填量与扰动后土壤侵蚀模数进行了相关性分析,并且定量、定性地研究了火电类生产建设项目各防治分区的水土流失特点和强度。研究结果表明,水土流失防治分区中临时堆土区的水土流失最为严重,平均侵蚀模数达到14747t/(km²·a),为水土流失重点监测和预防区。苏南、苏北不同地貌类型临时堆土区侵蚀强度差异较大。苏北平原沙土区临时堆土区土壤侵蚀强度最大,侵蚀模数达到14392t/(km²·a),苏南丘陵山区其次,均为极强度侵蚀单位面积土石方挖填量与扰动后土壤侵蚀模数存在线性正相关关系,土石方挖填活动对水土流失的影响敏感度大小排列次序为:丘陵山区(苏南)>平原沙土区>丘陵山区(苏北)>一般平原区(苏南)>一般平原区(苏北)。     

水土保持是水土流失区农业发展的基础

我国是一个水土流失面积较大、危害较重的国家。目前,水土流失面积达150万公里²,折合22.5亿亩,超过了耕地面积,约占国土的六分之一。北起黑龙江,南至海南岛,从西北的黄土高原,到东部的沿海之滨,水土流失遍及全国各地,严重威胁着我国的农业生产。解放三十年来,党和政府十分重视水土保持工作,共治理水土流失40万公里²,取得了很大成绩。但由于片面强调“以粮为纲”,到处毁林毁革开荒,再加上林彪、“四人帮”的干扰破坏,治理速度赶不上破坏,水土流失面积不但没有减少,反而     

西藏“一江两河”地区水力侵蚀的时空分异规律

[目的] 对西藏自治区“一江两河”地区土壤侵蚀强度及其时空分异规律进行分析,为该地区土壤侵蚀防治与生态治理提供科学依据。[方法] 基于降雨、数字高程模型DEM、土壤、植被及土地覆被等数据,利用修正通用土壤流失方程(RUSLE)及空间信息技术(GIS)等方法估算研究区1995,2005,2015和2020年的土壤侵蚀模数并进行土壤侵蚀强度分级,分析“一江两河”地区土壤侵蚀强度时空变化特征,阐明水土流失面积变化规律。 [结果] ①“一江两河”地区平均土壤侵蚀模数为30.35 t/(hm²·a),随时间呈先增加后降低的总体趋势,且土壤侵蚀模数呈减少趋势的区域面积逐年增加。 ②研究区土壤侵蚀强度呈西高东低的趋势,以轻度和微度为主,面积比例总和达70%及以上,各等级土壤侵蚀面积转移以中度侵蚀→轻度侵蚀为主。 ③流域内水土流失面积比例总体呈现减小趋势,谢通门县、拉孜县为侵蚀风险较高的区域。 [结论] “一江两河”地区土壤侵蚀具有较强的时空分异性,中部地区土壤侵蚀风险较高,水土保持治理亟需加强。     

淮河流域黄泛平原风沙区水土流失监管重点

为全面分析国家级水土流失重点预防区黄泛平原风沙区的土壤流失特征,确定区域水土流失监管重点对象和实施途径,基于全国水土流失动态监测项目,以淮河流域黄泛平原风沙区为例,介绍了水蚀和风蚀调查、土壤侵蚀强度及其严重指数评价的方法,分析了该区水土流失基本特征,提出水土流失监管应着力做好4个方面的重点工作:①全面做好区域风蚀预防,尤其是在作物比较茂盛前,做好耕地防护;②全面做好生产建设项目督查,督导建设单位全面落实水土保持方案,实现建设一个项目、防护一片土地的效果;③坚决依法杜绝滥垦滥伐、乱采乱弃现象,坚决依法禁止未批先建、未验先投现象;④持续督导林地和草地全面保护与治理,通过补植、封育、改良和扩展种植等,促使林草地植物群落不断优化、林草地面积不断增大、预防水土流失的功能不断提升。     

紫色土退化旱地的肥力恢复与重建

常规耕作的水土流失造成紫色土坡耕地土层浅薄化、土壤养分贫瘠化、土壤干旱化及土壤结构劣化等土壤肥力退化问题。 1 984～ 1 996年长期田间试验结果表明 ,聚土免耕通过垄沟网状结构可保持水土 ,其多年平均径流与土壤侵蚀模数分别为 65 7.7m3hm- 2 和5 30 .0tkm- 2 ,而常规耕作的相应值分别为 1 75 4 .0m3hm- 2 和 31 2 2 .0tkm- 2 ,通过聚土与改土结合 ,聚土免耕活土层厚度平均增加 1 1 .8cm ,聚土免耕耕作技术还通过垄沟强化培肥降低土壤容重 ,增加土壤有机质及N、P、K含量 ,改善土壤理化性状 ,恢复土壤肥力。聚土免耕作物产量比平作高 1 5 %～ 30 %。 1 996～ 1 998年秸秆覆盖实验结果表明 ,秸秆覆盖增加土壤有机质和养分含量 ,改善并维持土壤结构。聚土免耕与秸秆覆盖结合有利于土壤养分活化、土壤结构形成与维护 ,是紫色土退化旱地肥力恢复与重建的关键技术。     

宜昌市三峡库区水土流失综合治理及其成效

宜昌市长江上游水土保持重点防治区三峡库区土地总面积 8372 km2 ,其中土壤侵蚀面积 4 710 .2 2km2 ,占 5 6 .2 6 %。这里山高坡陡 ,降雨集中 ,崩塌、滑坡频繁 ,移民迁建任务重 ,水土流失严重。选择坡改梯、经果林基地作为突破口 ,实施点、线、面措施优化布局 ,达到条、块、带状分布格局 ,建成了综合防治体系 ,优化了土地利用结构和农业生产结构 ,水土流失得到初步控制 ,生态环境明显改善 ,具有特色的茶、柑等支柱产业发展迅速 ,有力地促进了社会经济的可持续发展     

楚雄市土地退化分析

楚雄市的土地退化以水蚀为主要动力,在云贵高原具典型代表性。全市退化土地面积１１５９．４４ｋｍ＾２,占总面积的２６．１７％,土地退化的危害有：降低土壤肥力,冲断桥梁,加剧自然灾害,毁坏水利工程,其形成原因中自然因素是,地形破碎,降水分布不均匀,地表物质疏松,人为原因是：人口快速增长增加对土地的压力,导致乱垦坡地,砍伐森林和超载放牧。     

Dust storm erosion and its impact on soil carbon and nitrogen losses in northern China

There is increased awareness of the environmental impacts of soil carbon (C) and nitrogen (N) losses through wind erosion, especially in areas heavily affected by dust storm erosion. This paper reviews the recent literature concerning dust storm-related soil erosion and its impact on soil C and N losses in northern China. The purpose of our study is to provide an overview of the area of erosion-affected soils and to estimate the magnitude of soil C and N losses from farmland affected by dust storm erosion.According to the second national soil erosion remote-sensing survey in 2000, the area affected by wind erosion was 1.91 million km², accounting for 20% of the total land area in China. This area is expanding quickly as the incidence of heavy dust storms has greatly increased over the last five decades, mainly as a result of the intensification of soil cultivation. The economic and ecological damage caused by wind erosion is considerable. Heavily affected areas show a loss of nutrients and organic carbon in soils and the heavily degraded soils are much less productive. Compared with the non-degraded soil, the C and N contents in degraded soils have declined by 66% and 73%, respectively. The estimated annual losses per cm toplayer of soil C and N by dust storm erosion in northern China range from 53 to 1044 kg ha^− 1 and 5 to 90 kg ha^− 1, respectively. Field studies suggest that soil losses by wind erosion can be reduced by up to 79% when farmers shift from conventional soil tillage methods to no-till. Thus shifting to no-till or reduced tillage systems is an effective practice for protecting soil and soil nutrients. Our study indicates that soil conservation measures along with improved soil fertility management measures should be promoted in dry-land farming areas of northern China. As erosion is a major mechanism of nutrient withdrawal in these areas, we plead for the development of accurate methods for its assessment and for the incorporation of erosion, as a nutrient output term, in nutrient budget studies.     

Land use and soil conservation strategies for potentially highly erodible soils of central-eastern Nigeria

In areas susceptible to erosion, there is the need for a comprehensive soil conservation programme so as to be able to prevent catastrophic soil erosion problems. The absence of such a programme in central eastern Nigeria, that has a total land area of 20 000 km², necessitated the drawing up of a soil conservation strategy for the area. The aim was to provide information for better land-use planning and proper environmental and soil management. To achieve this, topographic, soil and landform maps of the area at the scale of 1:50 000 were used to delineate into slope land units, viz: 0–4 per cent, <4 per cent, drainage basins and headwaters. These slope units and estimated soil erosion hazard units using the revised universal soil loss equation (RUSLE) were employed to form a general purpose land classification based on the USDA land capability classification and FAO framework on land evaluation.The soil loss tolerance of the area falls between 1·16 and 1·30 Mg ha⁻¹ yr⁻¹, while the erosion hazard units are considered generally suitable for the various land utilization types, with a number of limitations the main ones being erosion and waterlogging. The soil conservation measures proposed involved the application of bioenvironmental processes in the area and appropriate watershed management. The techniques proposed are those based on low input technology, affordable by rural farmers. It is concluded that these soil conservation measures will be adequate for sustainable agricultural production in the area. Copyright © 1999 John Wiley & Sons, Ltd.     

Comparison of Wind Erosion on Various Agricultural Lands

This investigation was conducted to compare wind erosion on three different agricultural lands (dryland, wastewater-irrigated land, and freshwater-irrigated land) in southeastern Iran. This region consists of 11500 km² of arid to semi-arid lands and is one of the driest regions of the country with high population density. Average annual rainfall of the region ranges between 50 and 60 mm. The temperature data indicate that July is the warmest month, when the temperature rises to more than 50 °C, and January is the coldest month of the year, with a minimum temperature of ?12 °C. The warm winds blow over the region of Sistan for about 120 days from June to September. The dominant wind directions are north and northwest. Twenty plots were designed randomly (in a completely randomized design) in this study to compare two irrigated areas, freshwater-irrigated land and wastewater-irrigated land, to dryland (control fields). The treatments were repeated three times. Ten data sets were taken during the experimental period, and the means were calculated and reported. The data indicated that wastewater-irrigated land benefitted from reduced soil erosion, increased soil fertility status (i.e., soil organic matter and nutrient contents), and increased soil moisture content. Soil losses by wind erosion in the wastewater-irrigated land, freshwater-irrigated area, and dryland in the study area were 185.2, 339.8, and 554.4 tons ha^?1, respectively. In addition, the study sites lost 1.3, 2.4, and 4.6 cm of soil by wind erosion, respectively.     

Response of erosion reduction effect of typical soil and water conservation measures in cropland to rainfall and slope gradient changes and their applicable range in the Chinese Mollisols Region,Northeast China

Mollisols are rich in organic matter, which makes them suitable for cultivation and for enhancing global food security. Mollisols are experiencing severe soil erosion due to overfarming and a lack of maintenance. Thus, suitable soil and water conservation measures (SWCMs) are needed to protect Mollisols. However, how SWCMs respond to changes in slope gradient and rainfall and their effective application area remain ambiguous. Using a long-term field observation dataset, meta-analysis, and statistical test methods, we reveal the typical erosion reduction effect of SWCMs and their responses to changes in slope gradient and rainfall. Next, we calculated a coupling factor, P·S, by slope gradient and rainfall in flood season to determine the effective SWCMs application threshold. Compared with bare land, no-tillage (NT), contour ridge tillage (CT), ridge hedgerows (RH), and terraced fields (TF) had an average erosion reduction coefficient of 91.5%. There was a significant exponential increase in the correlation between P·S and the soil erosion amount in plots with typical measures. According to this correlation and soil loss tolerance (200 t/km²), the upper limits of P·S (NT: 564 mm; CT: 885 mm; RH: 1135 mm) were determined and utilized to determine the effective application areas (NT: 311.40 10³ km²; CT: 320.86 10³ km²; RH: 323.72 10³ km²) at the plot scale. In wet years, the applicable area of SWCMs declined toward the low-elevation foothills and flat terrain. All the results are applicable when slope length within 20 m. These results provide a basis for the precise allocation of SWCMs in Mollisols area and promote the scientific utilization of Mollisols resources.     

应用遥感技术对中国亚热带地区坡地利用及土壤侵蚀的研究

This paper introduces briefly two remote sensing case studies on land use in the subtropic region of China. One is on slope land use in the Yangtze River Three Gorges area. This is a large area of 60497 km². First of all, geometric correction and supervised classification were conducted for ten scenes of Landsat-5 TM or MSS images. The resolution of the processed images is 50 m × 50 m on ground. By the classification the land use/cover categories in this area were discriminated. Then the croplands including rice fields and upland fields were extracted from the land use/cover maps. Simultaneously the slope grade maps were prepared based on the topographic maps. Overlaying the slope grade maps and the cropland maps, the area and percentage of the croplands in different slope grades were determined. This case study indicated that 71.5% of the uplands was situated on the slope above 150 and 25% on the slope above 250 in this area. It is dangerous, and urgent cultivation or engineering measures should be taken. Another case study is on soil erosion in Linshan County of Guangxi Province. Airphoto interpretation and supervised classification of a Landsat TM image were carried out for discriminating land cover/use categories in an area of 3 557.8 km². And the soil erosion intensity grades were determined according to the land cover/use maps and slope maps. It wad discovered that the land suffering soil erosion accounted for 2404.0 km², 67.6% of the total area of the county. Necessary measures to control soil erosion should be taken also.     

The assessment of soil loss by water erosion in China

Soil erosion is a major environmental problem in China. Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information. The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011. A multi-stage, unequal probability, systematic area sampling method was employed. A total of 32,948 sample units, which were either 0.2–3 km² small catchments or 1 km² grids, were investigated on site. Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit, along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units. Maps were created by using a spatial interpolation method at national, river basin, and provincial scales. Results showed that the calculated average soil erosion rate was 5 t ha⁻¹ yr⁻¹ in China, and was 18.2 t ha⁻¹ yr⁻¹ for sloped, cultivated cropland. Intensive soil erosion occurred on cropland, overgrazing grassland, and sparsely forested land. The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids. The national average ratio was 13.5%, which represents the area of land in China that requires the implementation of soil conservation practices. These survey results and the maps provide the basic information for national conservation planning and policymaking.     

基于转移矩阵的准格尔旗土地利用变化分析

[目的]土地利用是影响水土流失变化的重要因子,通过分析准格尔旗土地利用类型动态变化情况,掌握该区各土地利用类型变化去向,为分析该区水土流失状况提供依据。[方法]采用土地利用转移矩阵方法研究准格尔旗土地利用变化特征。[结果]2014—2016年,准格尔旗各土地利用类型变化不显著,表现为林地、草地、水域及水利设施用地占地面积分别减少16.02,12.66和2.48km^2,居民点及工矿交通用地、其他土地、耕地的占地面积分别增加18.63,10.53和1.72km^2;该区水土流失面积增加70.8km^2。[结论]准格尔旗减少的林地和草地主要转变为居民点及工矿交通用地和其他土地。结合水土流失数据分析表明,该区域水土流失面积的增加与林地和草地面积减少,以及林地和草地植被覆盖度的变化有关。